An experiment scheme and understanding trial.

The Lorentz force is a free force and is not connected with external mediums. It usually occurs when a conductor with current flow is located inside magnetic field. The force is not related with any external mass ejection reactions like in rocket engine and could be a propulsion method in order to journey in vacuum in a case of some technologically advanced space vehicle. Magnetic force is rising due to electron flowing in the conductors thanks to magnetic field of permanent magnets or electromagnets. The stronger magnetic field, the stronger force is rising, also the greater number of electrons is in magnetic field range due to electric current, the force is also stronger. 

A Lorentz force: